Patent GB-675656-A (GB)
Title: Improvements in and relating to the manufacture of light sensitive photographic emulsions
Inventor: DORMAEL ANDRE EMILE VAN
IPC: G03C1/12
Filed: 1948-10-15
Abstract: 2 : 21 - Dinitro - 4 : 41 - di - p - tolyldiphenyl disulphide is prepared by heating 4-methyl-31-nitro-41-bromodiphenyl, sodium sulphide, and sulphur in alcohol.  2 - Methyl - 5 - p - tolylbenzthiazole is prepared by refluxing the zinc salt of 2-amino-4-p-tolylthiophenol (obtained by reducing 2 : 21-dinitro - 4 : 41 - p - tolyl - diphenyl disulphide in acetic acid with zinc and HCl) with acetic acid and acetic anhydride.  2 - Benzoylmethylene - 3 - methyl - 5 - p - tolyldihydrobenzthiazole is prepared by reacting 2-methyl - 5 - p - tolylbenzthiazole dimethylsulphate with benzoyl chloride in pyridine.  2 - Thiobenzoylmethylene - 3 - methyl - 5 - p-tolyldihydrobenzthiazole is prepared by treating 2 - benzoylmethylene - 3 - methyl - 5 - p - tolyldihydrobenzthiazole with phosphorus pentasulphide in chloroform.  2 - (b  - Methylmercapto : b - phenylvinyl) - 5-p-tolylbenzthiazole dimethylsulphate is prepared by refluxing 2-thiobenzoylmethylene-3-methyl-5-p-tolyldihydrobenzthiazole with dimethyl sulphate in benzene.  4 - Methyl - 31 - nitro - 41 - acetylaminodiphenyl is prepared by nitrating 4-methyl-41-acetylaminodiphenyl in acetic acid, and 4-methyl - 31 - nitro - 41 - aminodiphenyl is prepared therefrom by hydrolysing with aqueous KOH.  4 - Methyl - 31 - nitro - 41 - bromodiphenyl is prepared by diazotizing 4-methyl-31-nitro-4-aminodiphenyl and treating with cupric bromide in aqueous HBr.  p - (1 - Naphthyl) - aniline hydrochloride is prepared by reducing 1-(4-nitrophenyl)-naphthalene in acetic acid with acidified stannous chloride.  6-(1 - Naphthyl) - phenylene - thiaz - thionium chloride is prepared by adding p-(1-naphthyl)-aniline hydrochloride to sulphur-monochloride and stirring, adding dry benzene, and refluxing. On stirring the product with water, 6-(1-naphthyl) - phenylenethiaz - thionium hydrate is obtained.  2 - Amino - 5 - (1 - naphthyl) - thiophenol (zinc salt) is prepared by adding aqueous NaOH to an aqueous suspension of 6-(1-naphthyl)-phenylenethiazthionium hydrate, filtering, and adding zinc chloride.  2 - Methyl - 6 - (1 - naphthyl) - benzthiazole is prepared by refluxing together the zinc salt of 2-amino-5-(1-naphthyl)-thiophenol, acetic acid, and acetic anhydride, distilling off the acetic acid in vacuo, and treating with NaOH. Specification 675,654 is referred to.ALSO:3 : 31 - Diethyl - 6 : 61 - di - a  - naphthylthiacarbocyanine iodide is prepared by refluxing together 2 - methyl - 6 - a  - naphthylbenzthiazole etho-p-toluenesulphonate and ethyl orthoformate in pyridine, and treating with aqueous KI solution.  A complex merocyanine dye is prepared by heating 3 - allyl - 5 - [(3 - methyl - 5 - p - tolylbenzthiazolylidene) - a  - phenylethylidene] - rhodanine with methyl p-toluenesulphonate and refluxing the product with 2-methyl-4 : 5-diphenylthiazole ethiodide in pyridine containing triethylamine. 3 - Allyl - 5 - [(3 - methyl - 5 - p - tolylbenzthiazolylidene) - a - phenylethylidene] - rhodanine is prepared by refluxing together 2-(b -methylmercapto : b  - phenylvinyl) - 5 - p - tolylbenzthiazole dimethylsulphate and N-allylrhodanine.  Specification 675,654 is referred to.